1. Field of Invention
The invention relates to a printing system and a printing apparatus that perform a virtual printing operation based on print data.
2. Description of Related Art
There has been a printing apparatus, such as a printer, that performs printing onto a recording medium, based on print data received from a print data transmitting device, such as a personal computer. For the printing operation, the printing apparatus conveys a predetermined recording medium, such as sheets, by a sheet conveying mechanism, and applies a developing agent, such as ink or toner (black or a plurality of colors), onto the recording medium. The printing apparatus has a function of transmitting error information to the print data transmitting device in the case where an error occurs in the process of printing when being performed according to the received print data. When receiving the error information from the printing apparatus, the print data transmitting device performs processing for informing a user of the occurrence of the error during the printing operation, based on the error information.
For example, there may be a case where the printing apparatus becomes unable to store additional print data into memory. When such happens, the printing apparatus transmits a memory full error to the print data transmitting device. Then, the print data transmitting device displays a message, to the effect that a memory full error has occurred in the printing apparatus, on a display connected to the print data transmitting device, and/or transmits information of the occurrence of the memory full error to a user terminal connected to the print data transmitting device. Likewise, when the printing apparatus runs out of recording medium during the printing operation, the printing apparatus transmits a recording medium empty error and the print data transmitting device performs processing for informing the user of the lack of recording medium. As described above, the user becomes aware of the error that occurred in the printing apparatus during the printing operation on the recording medium.
However, there may be a case where the user is informed of the error while the sheet conveying mechanism is driven and a developing agent is adhered to the recording medium. In this case, the recording medium, to which the developing agent has been adhered before the error occurs, will be wasted.
It is assumed that, in a printing apparatus that prints print data by storing the print data in the memory by page, a memory full error occurs during attempted storage of print data of greater than a page in the memory. In this case, the printing of a page, during which the memory full error occurs, cannot be performed unless the memory of the printing apparatus is increased. Therefore, when this case happens, the user transmits the rest of the print data, which has not been printed, to another printing apparatus, which has sufficient free memory space, to print the print data.
When the page, at which the error occurs, and the rest of pages are printed by the other printing apparatus, consistency in a print result through the document is lost because the shape of fonts and objects, colors, and color density vary among the printing apparatuses. Therefore, in order to maintain print consistency, all of the pages of the document need to be printed again by a printing apparatus having sufficient memory space.
Especially, when the memory full error occurs while the last part (near the last page) of the print data is being stored, a plurality of sheets have already been produced containing the first part on the print data thereon. Therefore, if all of the print data is printed again by the other printing apparatus, the sheets, which have been already printed by the original printing apparatus with the print data, will be wasted.
The above situation may happen not only in a case where the memory full error occurs. There are other cases, for example, where print data cannot be interpreted due to a disparity in the printing program (emulation), where the printing apparatus runs out of recording medium of a desired size, where the number of sheets of recording medium remaining in the printer become low, and where the rest of print data is printed at lower resolution when it is determined that the memory is nearly full. The above situation also happens in a case where a buffer of an adhering unit overflows with data because print data is stored one after another in the buffer of the adhering unit even though the adhering unit has not yet outputted the print data (the buffer overruns), and in a case where the transmission of the developed print data to the adhering unit cannot be synchronized.